Castro

Hi everyone need some advise...Went to inspection after being online for about 1 1/2 when it was my turn to get in my z28 started to let out a bit of white smoke from the exhaust causing me to fail inspection.

Next Steps:
1. Tune up - New plugs, new wires (Checked the engine timing and tweaked so it was perfect), new distributor cap, new rotors, oil change. Took car to get coolant flushed. and put in a new thermostat.

2. The first time i changed the plugs I had purchased Bosh platinum 4's. After installing them the car had this really rough idle which i thought was being caused by the plugs (I could feel it when I was in drive standing still very slight but it was there). I did some reading here and some people said that it happens sometimes with those plugs. So I went back in and pulled out the 4's and just went with regular bosh platinums.

>>>I noticed that the bosh plugs after only 1 week maybe like 150 miles had this black kind of burned ashy substance on the ring of the spark plug (All 8 of them). I had to scrape it off with a screw driver so i could return them. That is a big sign to me. New plugs should not have anything on them.<<<

Results after reinstalling new plugs again:
1. Car starts to smoke after its been run for awhile (1/2 hour or so). Especially if I get caught in any type of traffic. When I accelerate you see that it comes out a bit. The tune up did not fix the problem and now I have a little bit of shake happening when I am in drive.

Signs:
- I have noticed that all of sudden whenever I get caught in traffic the car gets really hot. 260 degrees sometimes...I have to pop the hood and keep moving to bring the temp back down. Considering that the cooling system has recently been flushed there is something definately wrong.

Next Steps:
- I am at a loss right now. I have read the boards and it might be a blown head gasket among several other things. I talked to a mechanic and he gave me all these posibilities too.

The boards tell me to get a engine compression test done.

With all these signs (black on new spark plugs, overheating, rough idle) I think there has to be an easy answer at this point.

The car has 90k on it.

aklim

We can make a few SWAGs and you might stumble on it. However, if it is white smoke, I'd recommend checking your coolant and oil regularly. If you see chocolate milk shake in your oil, you do have a coolant leak. That or if you see oil in your coolant.

Run a compression and leakdown test and see what you get.

rickyzZ28

Yes difinately check the cooolant as white smoke means antifreeze is being burned in the cylinder. As stated above do a compression/leakdown test. You should have steady numbers accross the board, if one is low you will probably find your problem.

SS CAM

Sounds like you got a head gasket going on you.

Marc 85Z28

Again, do a compression test. That will tell you if a problem exists. However, it could be the rings, valves, gaskets, etc. The only easy way to tell if the head gasket is blown is to blow compressed air into the spark plug hole with the radiator cap off. If bubbles come out, you need a gasket

TheGreatJ

The blackened plugs...was it just a couple of cylinders or the whole set? If it was the whole set then it probably isnt a gasket problem, as that would only affect the cylinder in which the leak was occuring. I've heard of a few people having problems with the +4's and won't run them myself, they could be the reason for the blackening.

If the compression/leakdown check comes back good I'd be lead to think it was the intake gasket leaking coolant into an intake runner. DEFINITELY keep a close eye on your coolant and oil.

Castro

Everyone thanks for the initial feeds.

As far as the plugs...yup they all had that black coating on the top ring of the plug. My friends suggested that it might be that my car is running to rich but I don't think that makes sense. The original gm plugs i pulled out of there had the coating too.

Ok so I am going to go to the mechanic and ask them to perform compression leak down test? I want to go in armed verbally as well so they at leat think i have seemy of an idea of what I am talking about.

Heres what i gather so far...I want a compression test done. Can anyone define what exactly gets done and how it is done and what the numbers etc will mean when I get the results. I want to really understand whats going on and learn =)

TheGreatJ

A compression test basically just tells you how much the engine is compressing the air/fuel mix before igniting it. Basically you pull all 8 plugs, then thread the tester (looks like a gauge with a hose and a valve on it) into the #1 plug hole. Then turn the engine over twice to compress the cylinder and write down how much pressure the gauge reads. Take the tester back out and press the button to release the pressure, and proceed to the next cylinder. Do this with all 8 and compare the readings. If a cylinder is more than 10% lower than the rest then you have a bent valve or blown head gasket or broken rings.

To be honest though I doubt this is gonna turn up anything. It seems like it's affecting all 8 cylinders more or less equally, which a gasket problem wouldnt do. But if it were me I'd do it anyway to be sure.

Drkhrse89

Black plugs tell me that it is running rich and the fact that your other plugs were black it may have been doing it for a while. Are you sure your smoke is white? Cause if it is a grayish black then you are running rich for sure. If you have access to a scan tool I would plug that in and see if you are running rich. Your A/F ratio should be right around 14.7:1. That is my $.02 hopefully that is some sort of help.

Castro

Ya I don't have the equipment to check the fuel ratio but its definately something I can mention to the mechanic once I kinda figure out what is going on.

Smoke looks totally white to me but again only comes out after awhile that the car has been running and hot u know what i mean? I am going to see if i can take some video

Also check out this pic I found.
http://www.centuryperformance.com/im...h/Plgheat1.jpg

Now this is what my plug looked like around the ring part not the bottom were the red is. Just the ring...the unsulator was white so just take a look at the ring (see the black). I was able to scrape all of it off with a screw driver but it was caked on or burned on kind well after only a week. I might pull of a plug this week after i re put the thermostat gasket back on cause its leaking a bit.

Damn its kinda if hard for me to imagine why the car is overheating everytime i am in traffic. The coolant isn't dissapearing from what I see either.

Also I realized that I didn't mention that A few weeks ago I took the car to the mechanic to check out an engine code that popped up after i changes the plugs and wires etc. Turned out the egr vac line got disconnected somehow I don't think this is what causing the overheating cause its all plugged back in.

The car heats up to 260 degrees if i hit any light traffic at all...

Drkhrse89

Ok the guages are not always accurate. I had the same problem and here are some of the things that made it alright for me. First off I found out that the fan was not coming on at all so I changed out the CTS (right under the throttle body very easy). Then it still wasnt right so I pulled my radiator and cleaned the crap out of it front and back and infront of it behind the condensor. Still wasnt right then I changed the temp within my chip and that did it for a while and then right back to the problem. I then thought about getting the fan switch to help even more but I found that my coolant was going low so I looked for a leak and found that my lower radiator hose was shot and so was the water pump. I am not saying that is your problem but that is what I ran into.

Is your coolant going down at all while you drive? Ok worded wrong has your coolant gone down since you flushed it? If so I would look for an external leak and then think the worst.

Castro

DKHorse thanks for the suggestions...some more little history. I put together a little summary at the end...sorry for all the detail...

After about 6 month's after I got the car (4 years ago) I noticed that I had some coolant coming up out of the first bolt right next to the thermostat. So I figured that the gasket (intake gasket) was on its way out. This was about 1 1/2 years ago I took off the TPI and changed that gasket and of course installed everything back in to torque specs. I could have just tried to tighten the bolt down but in reality it was impossible cause its a torque bolt and I couldn't cut that sharp of an angle. At that time I saw that there was alot of sludge inside the block (once the intake was off) Indicating to me that the owner wasn't really into changing the oil on the car often (I got the car with 69k)

Well I cleaned out as much of the sludge as I could and reassembled everything. Then at the end of that I set the cars timing and everything was back to normal. No more coolnat coming up from the bolt car was running smooth...

About 6 months later I started to get a drop coming out of the water pump. So I changed that and everything was fine again.
So my water pump is not that old.

I also checked to see if my fan is coming on at 220 and it is i think the other kicks on at 260 but I can't recall now. I have not seen that one kick on. Maybe I should check that out.

Now that the car has been overheating I again noticed that a bit of coolant shot up that bolt again. That really sucks! It seems to be a real over heating issue and when it hits that high 260 coolant starts coming up.

Not sure if any of this is related to the car heating up now...and the rough idle when I am in drive.

Summary:
- Intake gasket pretty new
- Water pump is pretty new

Drkhrse89

The second fan is used when the A/C is on, or if you get the fan switch from Jet or the like it will lower the temp it turns on. I am almost positive that it will come on at 260*.

This is a real extreme example but I had a problem very similar to this and it turned out to be a cracked block. When ever the car would heat up the crack would open up just a little and cause the coolant to bubble up and over heat like crazy. I know that is very extreme but like I said I had the exact same issue. The way that I fixed it (in order to trade the car in on my IROC) I just pulled out the T-Stat.

I am really baffled on this one. So when you are driving at a normal speed it will not heat up just when you are at a stand still huh?

Castro

Hey DrkHorse,

yup the car heats up when I get into stop and go traffic.

The funny part is until I gave the car the tuneup I didn't have a problem from what I remember. After I changed the plugs and wires is when I saw the overheating issue and also the car started to get a rough idle when I was in drive and stopped. Thats why my thinking was the plugs originally.

Normal speeds car's temp is normal.

I asked another mechanic what kind of tests he could run and he started saying this and that but never mentioned "a compression test"

This weekend I am going to fix the thermostat gasket and then take some video and pics of the problem see if it helps...